The present invention relates to printer devices. More particularly, the invention relates to a gear clutch assembly and method for operating a transfix roller and a drum maintenance system using a single motor without electromagnetic solenoids or clutches and will be described with particular references thereto. However, it is to be appreciated that the present invention may also be amendable for other applications.
In many print devices, an intermediate transfer surface, such as a transfer drum, is used to deliver printer ink from a print head to a print or receiving medium such as paper. More specifically, ink is ejected from jets in the print head onto the transfer drum creating a liquid layer of ink. The receiving medium is then brought into contact with the transfer drum and the ink image is transferred and fused or fixed to the receiving medium.
To assist in the transfer and fixing of the ink image, a transfix roller is often utilized to apply a pressure to the receiving medium thereby pressing the receiving medium against the transfer drum. When or around the time the receiving medium engages the transfer drum for transfixing of the image on the receiving medium, the transfix roller is moved from an idle unloaded or disengaged position toward a loaded or engaged position. In the loaded position, the receiving medium is sandwiched between the transfer roller and the transfer drum. After the ink image is transfixed on the receiving medium and the receiving medium is ready or about ready to disengage from the transfer drum, the transfix roller is moved from the loaded position toward an unloaded position to permit the receiving medium to exit from the transfix roller and transfer drum. The transfix roller remains in the unloaded position until the next transfix operation occurs.
After the ink is transfixed to the receiving medium from the transfer drum, the transfer drum requires conditioning for a subsequent ink jetting from the print head. Typically, a drum maintenance system is used to condition the transfer drum for receipt of the next ink image. The drum maintenance system, when activated, moves from an idle or disengaged position to an operating or engaged position. In the engaged position, a roller included in the drum maintenance system applies an oil or other similar functioning substance to the transfer drum. The oil reduces the probability that ink sprayed onto the transfer drum will stick to the transfer drum during the transfix operation. The drum maintenance system also includes a plastic or rubber blade that approaches or engages the transfer drum when the drum maintenance system is in the engaged position. The blade meters the oil being applied to the transfer drum. While the drum maintenance system is in the engaged position, the transfix roller remains in its idle unloaded position. Upon completion of the drum maintenance operation, the drum maintenance system is moved to its idle position.
Typically, the transfix roller and the drum maintenance system are cam driven. That is, each of the transfix roller and the drum maintenance system are driven by independent cam mechanisms, a transfix cam mechanism and a drum maintenance cam mechanism. The prior art generally recognizes two systems or methods of operating the transfix roller and drive maintenance system cam mechanisms. First, two separate motors may be used. The first motor would drive the transfix cam mechanism and the second motor would drive the drum maintenance cam mechanism. A disadvantage of the two motor system is the cost for including two such motors in a print device and the spacial and volumetric constraints of print devices.
In the second prior art system, a single motor is used to drive both the transfix cam mechanism and the drum maintenance cam mechanism. Independent control of the cam mechanisms is achieved through the use of electromagnetic clutches or electromagnetic solenoids. There are several disadvantages in the single motor/electromagnetic clutch or solenoid system. First, electromagnetic clutches and solenoids are unreliable as they tend to fail and render their print devices inoperable. Second, although not always as costly as the two motor system, electromagnetic clutches and solenoids are still costly to include in competitive print devices. Third, single motor/electromagnetic clutch or solenoid systems do not permit operation of the cam mechanisms simultaneously. Simultaneous or concurrent operation allows the drum maintenance system to be moved toward the engaged position at the same time that the transfix roller is moved from the loaded position to the unloaded position. Such simultaneous operation increases the speed and efficiency of the print device. Thus, there is a need to provide a single motor system in a print device that will independently operate a transfix roller and a drum maintenance system via a pair of cam mechanisms. Such a system should permit concurrent operation of the transfix roller and the drum maintenance system while reducing reliability issues and cost implications.
The present invention provides a new and improved gear clutch assembly and method for operating a transfix roller and a drum maintenance system within a print device for overcoming the above-referenced drawbacks and others.
In accordance with the present invention, a gear assembly for a print device is provided. More particularly, in accordance with this aspect of the invention, the gear assembly includes an input gear connected to a drive shaft of a motor. The gear assembly further includes a first output gear and a second output gear. The first output gear operates a transfix roller in the print device and is spaced relative to the input gear to allow teeth of the input gear to mesh with teeth of the first output gear. The first output gear includes a first toothless portion that does not mesh with teeth of the input gear when the input gear is adjacent the first toothless portion. The second output gear operates a drum maintenance system in the print device and is spaced relative to the input gear to allow teeth of the input gear to mesh with teeth of the second output gear. The second output gear includes a second toothless portion that does not mesh with teeth of the input gear when the input gear is adjacent the second toothless portion.
The gear assembly further includes a swing arm for rotating the first output gear when the input gear is adjacent the first toothless portion and the second output gear when the input gear is adjacent the second toothless portion. Said rotation of the first output gear moving the first toothless portion away from the input gear and allowing teeth of the input gear to engage teeth of the first output gear. Said rotation of the second output gear moving the second toothless portion away from the input gear and allowing teeth of the input gear to mesh with teeth of the second output gear.
According to another aspect of the present invention, a new and improved print device is provided. More particularly, in accordance with this aspect of the invention, the print device includes a transfer drum for transferring an image to a print medium and a transfix roller for applying a pressure on the print medium against the transfer drum. The print device further includes a drum maintenance system for preparing the transfer drum for subsequent image transfers to the print medium. A first cam assembly is provided for moving the transfix roller between a loaded position where pressure is applied to the print medium against the drum and an unloaded position. A second cam assembly is provided for moving the drum maintenance system between and engaged position wherein the drum maintenance system is capable of preparing the transfer drum for a subsequent image transfer and an idle position.
The print device further includes a single-motor and gear arrangement for selectively moving the first and second cams to control the transfix roller and the drum maintenance system. The arrangement includes a motor having a drive shaft and an input gear connected to the drive shaft.
The arrangement further includes a first output and a second output gear. The first output gear is rotatable between a first output gear engaged position and a first output gear home position. Teeth of the input gear mesh with teeth of the first output gear in the first output gear engaged position and rotation of the input gear will rotate the first output gear. A toothless section of the first output gear is aligned with the input gear in the first output gear home position wherein rotation of the input gear will not rotate the first output gear. The second output gear is rotatable between a second output gear engaged position and a second output gear home position. Teeth of the input gear mesh with teeth of the second output gear in the second output gear engaged position and rotation of the input gear will rotate the second output gear. A toothless section of the second output gear is aligned with the input gear in the second output gear home position wherein rotation of the input gear will not rotate the second output gear.
The arrangement further includes a swing arm connected to the drive shaft that is movable between a swing arm first engaged position and a swing arm second engaged position. In the swing arm first engaged position, the swing arm is capable of moving the first output gear from the first output gear home position to the first output gear engaged position. In the second swing arm engaged position, the swing arm is capable of moving the second output gear from the second output gear home position to the second output gear engaged position. The first output gear is adapted to move the first cam assembly upon rotation of the first output gear thereby moving the transfix roller between the loaded and unloaded positions. The second output gear is adapted to move the second cam assembly upon rotation of the second output gear thereby moving the drum maintenance system between an engaged position and an idle position.
According to still another aspect of the invention, a method of controlling a transfix roller and a drum maintenance system using a single motor and gear arrangement is provided. More particularly in accordance with this aspect of the invention, the method includes the step of rotating an input gear in a first direction to move a swing arm into engagement with a first output gear and rotate the first output gear away from a first output gear home position. A transfix roller is in an unloaded position when the first output gear is in the first output gear home position. The input gear is continued to be driven in the first direction to rotate the first output gear when the first output gear is away from the first output gear home position. Rotation of the first output gear to a predetermined position causes a transfix roller to move toward a loaded position.
The input gear is rotated in a second direction to move the swing arm into engagement with a second output gear and rotate the second output gear away from a second output gear home position. A drum maintenance system is in an idle position when the second output gear is in the second output gear home position. The input gear is continued to be driven in the second direction to rotate the second output gear when the second output gear is away from the second output gear home position. Rotation of the second output gear to a predetermined position causes a drum maintenance system to move toward an engaged position.
According to another aspect of the invention, a gear clutch assembly for operating a transfix roller and a drum maintenance system in a print device is provided. More particularly, in accordance with this aspect of the invention, the gear clutch assembly includes an input gear adapted to be driven by a motor and a means for moving an associated transfix roller into engagement with an associated transfer drum when the input gear is rotated in a first direction. The gear clutch assembly further includes a means for disengaging the associated transfix roller from the associated transfer roller while concurrently moving an associated drum maintenance system into engagement with the associated transfer drum when the input gear is driven in a second direction. The gear clutch assembly further includes a means for disengaging the associated drum maintenance system from the associated transfer drum when the input gear is rotated in the first direction.
According to still another aspect of the invention, an electrographic machine is provided. More particularly, in accordance with this aspect of the invention, the electrophotographic machine includes a transfer drum for temporarily receiving an ink image thereon and transferring the ink image to a print medium. A transfix roller assembly having a transfix roller for pressing a print medium against the transfer drum and a drum maintenance system assembly for conditioning the transfer drum are also included. The electrophotographic machine further includes a gear clutch assembly having a drive gear driven by a motor. A first output gear is connected to the transfix roller assembly and adapted to move the transfix roller upon rotation of the drive gear. A second output gear is connected to the drum maintenance system assembly and is adapted to move the drum maintenance system upon rotation of the drive gear. The drive gear is normally disengaged from the first and second output gears. The gear clutch assembly includes a swing arm that upon movement in a first direction causes the drive gear to engage the first output gear and upon movement in a second direction causes the drive gear to engage the second output gear. Rotation of the drive gear in a first direction moves the swing arm in the first direction and rotation of the drive gear in a second direction moves the swing arm in the second direction.
A primary advantage of the present invention is the provision of a gear clutch assembly and method for operating a transfix roller and a drum maintenance system in a print device that uses a single motor and does not require electromagnetic solenoids or clutches.
A further advantage of the present invention is the provision of an assembly for operating a transfix roller and drum maintenance system that is more reliable and less costly than other operating alternatives.
A further advantage of the present invention is the provision of a gear clutch assembly that allows either or both the transfix roller and the drum maintenance system to be selectively, independently driven.
A still further advantage of the present invention is the provision of a gear clutch assembly that allows simultaneous or concurrent driving of the transfix roller and the drum maintenance system.
Further advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the following detailed description of the preferred embodiment.